<?php


// echo 'hello world';

//可变变量
$name = 'school';

$$name = 'hello world';   //$$name = school

echo $school;      //hello world


//传址变量
$a = 5;
$b =& $a;   //把a的空间给b
$b  = 10;   //给b赋值相当于给a赋值
echo $a;    //10